Sensor guided epicardial lead

Abstract

Implantable cardiac monitoring and stimulation methods and devices with epicardial leads having sensor feedback. A fixed or extendable/retractable sensor may be displaceable within the lead's lumen and configured to sense the presence of an anatomical feature or physiological parameter of cardiac tissue in proximity with the lead body's distal end. The sensor may include an ultrasonic sensing element, a perfusion sensor, a photoplethysmographic sensor, or a blood oximetry sensor. Methods of determining suitability for implanting a lead involve the steps of accessing an epicardial surface of the heart, and moving the cardiac lead to an implant site at the epicardial surface. A transmitted signal is directed at the implant site. A reflected signal is received, indicative of the presence of a blood vessel at the implant site. A determination may be made to determine whether the implant site is suitable or unsuitable based on the reflected signal.

1. A method of determining suitability for implanting a cardiac lead on a surface of a patient's heart, comprising:
 accessing, via a patient's chest cavity, an epicardial surface of the heart; 
 moving the cardiac lead to an implant site at the epicardial surface; 
 stabilizing the lead at the implant site; 
 transmitting a signal from the lead directed at the implant site; 
 receiving at the lead a reflected signal resulting from the transmitted signal indicative of the presence or absence of a blood vessel at the implant site; and 
 determining whether the implant site is suitable or unsuitable for implantation of the cardiac lead at least in part using the reflected signal. 
 
     
     
       2. The method of  claim 1 , comprising:
 determining a physiological parameter at the implant site; and 
 determining whether the implant site is suitable or unsuitable for implantation of the cardiac lead using the reflected signal and the physiological parameter. 
 
     
     
       3. The method of  claim 1 , further comprising generating blood-flow signals representative of blood vessel presence at or near the implant site using the reflected signal. 
     
     
       4. A method of determining suitability for implanting a cardiac lead on a surface of a patient's heart, comprising:
 accessing, via a patient's chest cavity, an epicardial surface of the heart; 
 moving the cardiac lead to an implant site at the epicardial surface; 
 transmitting, from the cardiac lead, ultrasonic energy directed at the implant site; 
 receiving, at the cardiac lead, ultrasonic energy reflected from the implant site; and 
 identifying the site as suitable or unsuitable for implanting the cardiac lead at least in part using the received ultrasonic energy. 
 
     
     
       5. The method of  claim 4 , further comprising detecting presence or absence of blood perfusion at the implant site using the received ultrasonic energy. 
     
     
       6. The method of  claim 4 , further comprising: detecting presence or absence of blood perfusion at the implant site using the received ultrasonic energy; and
 performing a pacing threshold test at the implant site; 
 wherein the site is identified as suitable for lead implantation in response to detecting an absence of blood perfusion at the site and obtaining an acceptable pacing threshold for the site. 
 
     
     
       7. A system for determining suitability for implanting a cardiac lead on a surface of a patient's heart, comprising:
 means for accessing, via a patient's chest cavity, an epicardial surface of the heart; 
 means for moving the cardiac lead to an implant site at the epicardial surface; 
 means for transmitting a signal directed at the implant site; 
 means for receiving a reflected signal resulting from the transmitted signal indicative of blood perfusion at the implant site; 
 means for determining an electrical parameter of tissue at the implant site; and 
 means for determining whether the implant site is suitable or unsuitable for implantation of the cardiac lead using the reflected signal and the electrical parameter. 
 
     
     
       8. A system for determining suitability for implanting a cardiac lead on a surface of a patient's heart, comprising:
 means for accessing, via a patient's chest cavity, an epicardial surface of the heart; 
 means for moving the cardiac lead to an implant site at the epicardial surface; 
 means for transmitting ultrasonic energy directed at the implant site; 
 means for receiving ultrasonic energy reflected from the implant site; and 
 means for identifying the site as suitable or unsuitable for implanting the cardiac lead at least in part using the received ultrasonic energy.